Surfactant effects on pH-controlled synthesis of nickel hydroxides

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2006-06, Vol.280 (1), p.23-31
• Main Authors: Coudun, Corinne, Grillon, François, Hochepied, Jean-François
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; Condensed Matter; Crystal growth; Direct micelle; Exact sciences and technology; General and physical chemistry; Materials Science; Micelles. Thin films; Morphology; Nickel hydroxide; Physics; Polymorphism
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2006.01.018

The aim of the present work is to determine at 60 °C, the influence of the specific nature of nickel salt and pH on nickel hydroxide features such as crystallographic structure and morphology. Within the range 8 ≤ pH ≤ 11.5, a home-made nickel functionalized surfactant, nickel di-dodecylsulfate Ni(C 12H 25SO 4) 2 is compared to usual salts (nickel nitrate Ni(NO 3) 2 and nickel sulfate NiSO 4). In both cases, a sharp transition appears for pH about 10. In the classic salt case, the transition mainly affects morphology, that could be evidenced by the crosschecking of complementary techniques as SEM and nitrogen gas adsorption. For pH < 10, β-Ni(OH) 2 platelets are yielded, whereas more basic conditions lead to randomly aggregated nano-grains of badly crystallized β hydroxide. Inversely, by employing the functionalized surfactant, 2D morphology is maintained in the whole pH-range, but the crystal structure is pH-controlled (α phase with interlamellar dodecylsulfate for pH ≤ 9.5, and β phase for pH ≥ 10.5).